As an inflator for an inflating type safety system of an automobile, in order to optimally protect a passenger in accordance with a position of a seat in a vehicle such as a driver side, a passenger side and the like, there are known various inflators such as an air bag inflator for a driver side, an air bag inflator for a passenger side, an air bag inflator for a side collision, an inflator for a curtain air bag, an inflator for a knee-bolster, an inflator for an inflatable seat belt, an inflator for a tubular system and an inflator for pretensioner. Among these inflators, the inflator for a curtain air bag inflates and develops an air bag instantaneously to form a curtain having a thickness of some centimeters over windows of a vehicle when the vehicle received the impact from the sides.
Such an inflator for a curtain air bag is structured such that discharge of pressurized medium starts by rupture of a rupturable plate and a curtain air bag is inflated and developed finally. Since so-called enhancer agent (a transfer charge) is not used, it is important to increase the rupturability of the rupturable plate in order to improve reliability in the operation of the inflator.
Not only the above inflator for a curtain air bag but also various inflators are required to be reduced in weight according to the requirement for weight reduction of a vehicle itself and simultaneously they are also required to be enhanced safety in actuation thereof. For example, when the inflator for a curtain air bag is actuated to inflate and develop the curtain air bag, a passenger views the curtain air bag and comes in contact therewith. Therefore, if foreign objects are inserted in the air bag, the passenger can be uneasy or alarmed or the air bag can be damaged. Accordingly, in a case that the inflator is provided as a product, it becomes important to eliminate such a problem.
In order to reduce size and weight, a manufacturing process of an inflator needs to be simplified because of a demand for reduction in the number of parts or manufacturing cost.
As related conventional techniques, a device for inflating a flexible container using helium and hydrogen is disclosed in U.S. Pat. No. 5,527,066. A gas flow device for an air bag using a pressurized inert gas is disclosed in U.S. Pat. No. 5,782,486. An air bag apparatus for inflating an air bag with nitrogen or helium is disclosed in U.S. Pat. No. 3,680,886. A side-collision inflator housing for an air bag using a pressurized gas and a gas generating agent is disclosed in U.S. Pat. No. 5,803,493. A pressurized gas inflator using argon or nitrogen as a pressurized gas is disclosed in JP-U No. 3031246.